E Kart sprocket I need your help

I built an E-Kart but I am finding it hard to find and figure out what gear ratio that will give me a top end of 60-70mph. The only sprocket I am finding for my motor is for a roller 40 or 50 chains. I wanted to do 15 teeth sprocket (motor) and 25 teeth on the axle.

The problem is finding a 428 sprocket with 15 teeth to fit on my motor... Do anyone know where i can find this sprocket or have a better idea...????

Spec
Controller: Alltrax SR-72400

Motor: ME1003
200 amps continuous (400 amps for 1 minute).
Power: 11.5 kW cont-- 23 kW pk
Voltage: 12-72 Volt rated
Speed: 3700 rpm @ 72V unloaded
Size: 8" OD, 7.4 " long (w/o shaft)
Shaft: 7/8"x 1-3/4", 3/16" key
Weight: 39 lbs.

Batteries Setup
A123 Pouch batteries? - YES
40Ah
Battery configuration 2p20s

Rear tire: Mojo 7.1/11.0-6

Hi,

I'm using these in my Motenergy motor, available in a good variety of teeth:

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.de%2Fulk%2Fitm%2F361334351983

These are for 22mm shaft for Honda gx160 and gx200 engines, you may find them in your area with these keywords.
They need a little grinding to be adapted to the required 7/8" (22,25mm) but it is easily done.

Why use 428 chain?
Even if you already have a 428 rear sprocket it can make sense (in the long run) to find a front sprocket and rear sprocket combination that's just bolt on.

Front wears more, will be replaced first, so if you need to adapt something every time then it can be a hassle.

I'd buy both front and rear sprocket in #40, it's cheap and easy to find, at least if you're not in sweden like me

larsb said:

Why use 428 chain?
Even if you already have a 428 rear sprocket it can make sense (in the long run) to find a front sprocket and rear sprocket combination that's just bolt on.

Front wears more, will be replaced first, so if you need to adapt something every time then it can be a hassle.

I'd buy both front and rear sprocket in #40, it's cheap and easy to find, at least if you're not in sweden like me

Click to expand...

I cannot find a #40 sprocket 50mm w/ key for a go kart axle

Kart axle sprockets are normaly mounted on a “sprocket carrier” which has the axle bore and key fitting .
The sprockets are flat with a 6 hole bolt on fitting to the carrier.
#40 may be a bit light for 23kw max,..i would plan to use the 219 series chain and sprockets that most racing karts use... a large range of sizes are available 60 - 99T
PS.. you need to know your tire diameter to figure the ratio for a set speed.
Standard kart rear tires are 11” OD, but you may be using something else ?

LiTrEx said:

Hi,

I'm using these in my Motenergy motor, available in a good variety of teeth:

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.de%2Fulk%2Fitm%2F361334351983

These are for 22mm shaft for Honda gx160 and gx200 engines, you may find them in your area with these keywords.
They need a little grinding to be adapted to the required 7/8" (22,25mm) but it is easily done.

Click to expand...

This is exactly what I used, hand reamed it to 7/8" and fits perfectly using one of these https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F351645530077 alongside a 50mm 428 sprocket it all works perfectly

The only thing is you will need a stepped key for the keyway because the size is different between the sprocket and drive shaft

Chinesium gamble
https://www.vmcchineseparts.com/products/chinese-atv-front-sprocket-428-15t

VMC Chinese Parts LLC
414 San Diego Rd.
Carbondale, IL 62901

Click to expand...

https://mogoparts.com/products/10-0314-15

Amazon
https://www.amazon.com/d/Motorcycle-Sprockets/Wingsmoto-Sprocket-428-15T-Motorcycle-Dirtbike/B010UQK31Y

Aliexpress
https://www.aliexpress.com/item/11T-12T-13T-14T-15T-16T-17T-18T-19T-Tooth-428-ID-20MM-Front-Engine-Sprocket/32834238764.html

Hillhater said:

Kart axle sprockets are normaly mounted on a “sprocket carrier” which has the axle bore and key fitting .
The sprockets are flat with a 6 hole bolt on fitting to the carrier.
#40 may be a bit light for 23kw max,..i would plan to use the 219 series chain and sprockets that most racing karts use... a large range of sizes are available 60 - 99T
PS.. you need to know your tire diameter to figure the ratio for a set speed.
Standard kart rear tires are 11” OD, but you may be using something else ?

Click to expand...

those are not racing sprockets for top end. this is a top end sprocket

https://www.accelerationkarting.com/nkpsteel428sprocket.html

markz said:

Chinesium gamble
https://www.vmcchineseparts.com/products/chinese-atv-front-sprocket-428-15t

VMC Chinese Parts LLC
414 San Diego Rd.
Carbondale, IL 62901

Click to expand...

https://mogoparts.com/products/10-0314-15

Amazon
https://www.amazon.com/d/Motorcycle-Sprockets/Wingsmoto-Sprocket-428-15T-Motorcycle-Dirtbike/B010UQK31Y

Aliexpress
https://www.aliexpress.com/item/11T-12T-13T-14T-15T-16T-17T-18T-19T-Tooth-428-ID-20MM-Front-Engine-Sprocket/32834238764.html

Click to expand...

That wont work on a ME1003 shaft

futurerel said:

Hillhater said:

Kart axle sprockets are normaly mounted on a “sprocket carrier” which has the axle bore and key fitting .
The sprockets are flat with a 6 hole bolt on fitting to the carrier.
#40 may be a bit light for 23kw max,..i would plan to use the 219 series chain and sprockets that most racing karts use... a large range of sizes are available 60 - 99T
PS.. you need to know your tire diameter to figure the ratio for a set speed.
Standard kart rear tires are 11” OD, but you may be using something else ?

Click to expand...

those are not racing sprockets for top end. this is a top end sprocket

https://www.accelerationkarting.com/nkpsteel428sprocket.html

Click to expand...

Those 428 sprockets are for use on karts with gearbox’s which have low rpm (2000 ?),, on the drive sprocket and low chain speed....Hence small axle sprockets.
Top level race karts are “direct drive” with much higher drive sprocket rpm (5-15,000) and hence they need a larger axle sprocket dia to suit road speeds.
8:1 sprocket ratios are common

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